The small business license is $499 and you only have to pay that if you want to statically link against QT without dealing with the LGPL. Dynamic linking Qt is the default, costs $0 and doesn't incur the wrath of the LGPL.
Is that $499 per platform? I'm using Lazarus right now (after QT sticker shock). It's pretty good and free. I rather like object pascal. TMS has a webcore product that runs out of Visual studio (non free)
which is also object pascal and generates an html/js SPA. i'm not affiliated with them at all. Just a fan.